The U.K.’s decision to leave the EU could lead to “increased migrant pressure” in the summer months, according to the CEO of Eurotunnel, at a time when French politicians are threatening to scrap a deal that allows Britain to stop migrants on the French side of the Channel Tunnel.

The Brexit vote could make migrants believe the border between the U.K. and France will become “a huge wall, similar to the Berlin Wall, almost impossible to overcome,” leading them to flood into the country while they still can, Jacques Gounon, the head of the company that operates the tunnel between Britain and France, said Monday, media reports.

Gounon's warnings come as Emmanuel Macron, the French economy minister, joined the call for an end to a bilateral deal that effectively moved Britain’s border with France to the French side of the Channel, according to reports.

Macron joined Calais Mayor Natacha Bouchart in calling for the Le Touquet deal, which allows U.K. border officials to stop migrants in France, to be scrapped.

For now, Gounon said he doesn't plan to change the way his company cooperates with U.K. border authorities.

"Because it is very efficient, we are catching and giving to the police force all the information in order to protect the site and to capture the migrants. I don't see what could be done more," he said.